Method of and apparatus for making steel



July 12, 1932.

H. w. PROTZELLER ET AL METHOD OF AND APPARATUS FOR MAKING STEEL Filed Feb. 11. 1928 s Sheets-Sheet 1 0 0 m w 5 w W m d 4 ,0 w/fl f 2 rd 1 fimfwfi w i J J 1 w 1mm m .48 5 M 0% 8 w m m l 2 pJ A K llllllwllllill wad WMMHHHHUHHIH A .W; T il|i|m F 0 0/ 5 MW W flu d fi 3 a. 05 .H /8 1 u f fl 5 W A M w J1 1% NM W III Imfen ors- I 013; W/fiafFeZ/er E Z/ P @ZME'IZ Q Lorne Jul 12, 1932.

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METHOD OF AND APPARATUS FOR MAKING STEEL Filed Feb. 11. 1928 '5 Sheets-Sheet 3 ITLWQTL on 42729 mafi /b" 6 6555 Ql J EIZTZKQJ and July 12 1932'. H. w. PROTZELLER ET AL 1 8 METHOD OF AND APBARATUS FOR MAKING STEEL 'File d Feb 11. 1928 5 Sheets-Sheet 4 WIIIZ/IIAL? July 12,- 1932. H. w. PROTZELLER ET AL ,6

METHOD OF AND APPARATUS FOR MAKING STEEL 5 Sheets-Sheet 5 Filed Feb.

Illlllll +1 r rrgzy Patented July 12, 1932 UNITED STATES PATENT OFFICE HARRY W. PROTZELLER AND GEORGE W. FINNEY, OF EAST CHICAGO, INDIANA MIE'I'HOD OF AND APPARATUS FOR MAKING STEEL Application filed February 11, 1928.

This invention relates to improvements in methods of and apparatus for making steel and it consists of the matters hereinafter described and more particularly pointed out in the appended claims.

The primary object of the invention is to provide a method of and apparatus for mak ing steel and especially alloy steel, which will insure a greater uniformity in the steel made and which is more economical in the use of the alloy employed, the latter representing quite an item in the making of steel at this time.

A further object of the invention is to provide a method and apparatus for this purpose which readily may be employed in connection with apparatus now used in the steel industry and therefore does not contemplate the scrapping or changing of such last mentioned apparatus.

Still another object of the invention is to provide a method and apparatus which is most advantageously employed in connection with a heat of molten metal after it is withdrawn from a furnace and when it is in the ladle for distribution to a battery of molds, whereby the characteristics of the metal may be more readily controlled and rendered uniform and wherein the alloy em ployed may be more intimately mixed with the metal thus reducing the amount of alloy necessary to attain the desired result.

The invention consists generally in the steps, acts and means, whereby the above mentioned objects, together with others as will hereinafter appear, are attainable and the invention will be more readily understood by reference to the accompanying drawings which illustrate that form thereof which we consider the best and most'practical at the present time.

In the drawings:

Fig. 1 is a view in front elevation of the improved apparatus embodying the invention as when employed in connection with a ladle and a part of its associated crane and by which the improved method may be conveniently carried out.

Fig. 2 is a view in side elevation thereof.

Fig. 3 is a vertical sectional view through Serial No. 253,543.

the apparatus on an enlarged scale as taken on the line 33 of Fig. 1.

Fig. 4 is a top plan view of the apparatus on a scale larger than that shown in Figs. 1 and 2.

Fig. 5 is 1 a horizontal sectional view through the apparatus as taken on the line 55 of Fig. 2.

Fig. 6 is a view partly in front elevation and partly in section on a further enlarged scale of the agitator. A

Fig. 7 is a view in side elevation of the bottom end part of the agitator.

Fig. 8 is a vertical sectional view through the bottom end of the agitator as taken on the line 88 of Fig. 6.

Fig. 9 is a vertical sectional view through the bottom end part of the cast metal portion of the agitator.

Fig. 10 is another vertical section through liqhe agitator as taken on the line 10-10 of Fig. 11 is a horizontal section through the agitator as taken on the line 1111 of Fig. 6.

Fig. 12 is a perspective view of one of a plurality of tubular refractory members employed in connection with the agitator.

Fig. 13 is a perspective view of another type of tubular refractory member employed in connection with the agitator.

Fig. 14 is a bottom plan view of the member shown in Fig. 13. i

As an example of the carrying out of the improved method of making an alloy steel, the same will be described in connection with producing manganese steel, the term manganese being used in the same sense of an alloy although We do not wish to be limited thereto, because the method as well as the apparatus may be employed in making other alloy steels, where the peculiar characteristics of the invention makes it of advantage to do so. The apparatus for carrying out the method in what we believe at this time to be the most advantageous manner is illusfrom a furnace such as an open hearth fursteel industry. Thus, no expensive apparatus is rendered useless but there is only added to the apparatus now employed certain mechanism'which easily fits in with said apparatus, whereby with onl a comparatively small added cost, any stan ard apparatus may be changed over to carry out the method, said cost being readily saved in the first few heats operated upon.

Referring now in detail to that embodiment of the apparatus employed to carry out the improved method, illustrated in the accompanying drawings 1 indicates as a whole a ladle such as employed in the steel industry and which includes the usual outer metallic shell 2 and refractory lining 3. Said ladle has a fiat bottom and an upwardly tapering side wall and in said bottom is a discharge opening 4 controlled by a. valve 5 whereby the heat may be discharged into the usual ingot molds. Said ladle also has the usual slag spout 4 at its top. At diametrically opposite points on the side wall of the ladle above its middle are laterally extending trunnions 6 adapted to be engaged by the bottom ends of a pair of crane hooks 7 carried by a horizontally disposed equalizer bar indicated as a. whole by the numeral 8 and which forms part of the crane equipment (not shown) for handling the ladle in the manner well known. In this instance the equalizer bar comprises a pair of parallel, edgewise disposed channels 9-9 with the flanges thereof directed outwardly and each channel is reinforced on its inner face by fiat bars 10-10. At the ends of said channels are bracing blocks 11-11 to receive the pins 12 by which the hooks 7 are pivoted to the bar about an axis parallel with said bar. Adjacent each end block 11 is a transverse shaft 13 upon which is mounted a plurality of sheaves 14 over which cables 15 are trained, said cables passing upwardly to the winding and unwinding drums of the associated travelling crane whereby the ladle as a whole may be raised and lowered.

The channels of the equalizer bar are further connected together at their middles by a plate 16 which engages on and is fixed to the top flanges of said channels, said plate having a. centrally arranged opening 16 therein and four corner like extensions, with two of said extensions 17-17 disposed at a right angle to the plane of the equalizer bar and with the other two extensions 18-18 disposed parallel with said channels. A suitable distance above this plate is a second plate 19 having a centrally arranged opening 19 and fourcorner like extensions, with two of said extensions 20-20 disposed in the plane of the extensions 17-17 of the plate 16 and with the other two extensions 21-21 disposed in the plane of the corners 18-18 before mentioned. On the top surface of plate 19 is fixed a pair of edgewise disposed 1,eee,eee

channels 22-22 parallel with the channels 9-9 of the equalizer bar and the channels 9-9 of the equalizer bar are connected to the channels 22-22 by vertically disposed fabricated members 23-23 respectively each consisting in itself of a pair of channels and lattice bars.

For the purpose of convenience, the plates 19 and 16 will hereinafter be referred to as the top and bottom plates respectively and these two plates are further connected together by upright fiat bars 24-24 which are fixed to the extensions 17 and 20 respectively of said plates, the bottom ends of said bars being bent inwardly and downwardly to be fixed to the bottom flanges of the channels 9-9 at the middle thereof as best shown in Fig. 3. This construction provides a rigid but open framework or cage from which other elements of the improved apparatus are. supported and actuated as will presently appear.

Associated with the open frame or cage just above described is an agitator supporting carriage 25, capable of a. longitudinal movement between said top and bottom plates 19 and 16 respectively. Said carriage comprises upper and lower spaced plates 26 and 27 respectively secured together in spaced relation by a circular row of bolts and sleeves 28 and 29 respectively as best shown in Fig. 3. ranged between and coaxially with the plates of said carriage is a spur gear 30 having an annular top hub portion 31 and a bottom hub portion 32 with a rectangular socket therein, the top hub portion having rotative bearing in a bushing 33 in the upper plate 26 of the carriage. Said gear also has top and bottom antifriction thrust bearings in the form of balls disposed in raceways in both faces of the gear and in both opposed faces of said carriage plates.

Associated with this gear is an agitator member indicated as a whole as at 35. Said member includes a tubular rectangular shaft 36 of desired length and the top end thereof extends into the socket of the hub 32 of the gear 30 and is removably secured therein by pins 37 engaged in openings formed partly in opposite sides of the shaft end and partly in opposite sides of the gear hub part providing said socket as best shown in Fig. 3. Slightly above the bottom end of the shaft is a horizontal wall 38 so as to provide below the same a socket 39 and on the top side of said wall is an upright rib or web 40. Extending laterally from opposite walls of said shaft near its bottom end so as to be arranged in a plane at a right angle to said rib 40 are hollow blades 41-41 which open into the interior of said shaft 36. Each hollow blade is elliptical in cross section and the major axis of each blade is disposed at an angle to the horizontal, with the major axis of one blade arranged opposite the like axis of the other blade, the lower portion of each blade forming the advancing edge thereof. Each blade is enclosed in a protecting sleeve 42 of refractory material, which Sleeve has a socket 43 at its inner end to receive the same. That portion of each sleeve beyond the socket is substantially solid but has an opening 44 therein, a slot 45 being formed in the outer end of said sleeve in the plane of the minor axis thereof. The inner end of each sleeve fits snugly up against opposed side walls of the shaft 36 and said sleeves are secured in place by a long rod 46 which passes through both sleeves,both blades and said shaft, the rod being locked against endwise displacement by wedges 47 disposed in the slots 45 and passing through the ends of said rod. After the parts are thus assembled, the slots 45 and outer end of the opening 44 are then filled up with a plastic refractory material.

The shaft 36 is also enclosed in a refraotory protecting sleeve made up of a plurality of endwise interengaging sleeves 4848 and those sleeves 48-48 in the plane of the blades are cut away on opposite sides as shown in Fig. 13 to have a snug fit against the inner ends of the blade sleeves 42. The bottom end of the shaft is protected by a plug 49 and this plug has a part 49 that fits into the socket 39 of the shaft 36, a pin 50 passing through suitable openings in opposite sides of the sleeve 48* and through the plug part 49 to secure said plug in place. In this respect the opposite side walls of the extreme bottom end of the shaft 36 are drilled out for the pin 50 and the ends of said pins are protected by sealing up the openings in the sleeve 48 by a suitable plastic material. On the shaft 36 below the gear 30 is provided a locking collar 51 that may be clamped in place by set screws 52 said collar engaging the topmostv sleeve 48 to prevent any movement of said sleeves. It is here pointed out that all joints between the various sleeves are rendered tight by suitable plastic refractory material which of course hardens in use so that in effect an integral protective structure is provided on the shaft and blades. At a point between the gear 30 and above the collar 51, there is provided a plurality of ventilating openings 53 in each wall of the shaft.

lVithin the shaft 36 is provided an air blast tube 54 which though fixed at its top end in the top end of the shaft, projects a short distance therebeyond. The bottom end of this tube is cut away to fit over the rib 40 and rod 46 so as to discharge air against the bottom wall 38 of said shaft 36. To insure a circulation of air'into and out of each hollow blade 41, we provide a pair of baflie ribs 41 each blade at the bottom and passes toward the outer end thereof where it turns to pass inwardly again at the top of each blade and then into the interior of the shaft 36 to be discharged to atmosphere out through the openings 53. Thus as will be apparent, the agitator which when in operative position is immersed in molten metal as will later appear, is ventilated and kept at that temperature which will greatly increase its life and usefulness. The manner in which air is supplied to the tube 54 will soon appear.

Means are provided for rotating the agitator and also for raising or lowering the same to the desired position, the rotating means being so constructed as to be operative, no matter what position theagitator happens to be in. The means just mentioned areas follows:

55 indicates a plurality of vertically disposed threaded shafts associated with the plates 16 and 19 respectively of the open frame work or cage, before mentioned, with two of said shafts extending between the corners 1717 and 2020 of said plates and with the other two of said shafts extending between the corners 1818 and 2 121 of said plates. The bottom ends of said shafts are suitably journalled in an'tifriction bearings 56 in the corners of the plate 16 while the top ends of said shafts project through similar bearings 56 in the top plate 19. to extend beyond the same where each shaft is there pro vided with a small sprocket 57. An endless sprocket chain 58 is trained about said sprockets 57 and on said plate 19 'at points between several of the cornersthereof are support ing idler pulleys 58 for said chain. As the sprockets 57-57 are disposed in the horizontal plane of the channels 2222, said channels are formed with suitable openings therein for the passage of the chain 58 therethrough. Pivote'd coincident with the axis of one of said shafts, just above the plate 19 is an L shaped bracket 59 upon which is mounted a driving sprocket 60 that engages the outer surface of the chain 58, between the first mentioned shaft and an adjacent one. This driving sprocket carries a bevelled gear 61 that meshes with a pinion 62 on the armature shaft 63 of a reversible motor 64 which is carried by said bracket. In said bracket is an arcuate slot 65 through which a bolt 66 threaded into one of the channels 22 extends. By swinging the bracket in one direction or the other, the proper tension may be imposed on the chain and the bracket is then locked in the desired position by tightening up the bolt 66. Thus when the motor 64 is in operation, it is apparent that all of the shafts are simultaneously driven in the same direction. Each shaft 55 has threaded engagement in a bushing or sleeve 67 clamped against rotation between the upper and lower plates 26-27 of the carriage 25. From the Uzi above, it is apparent, that when the motor 64 is running in one direction, the carriage is caused to move upwardly in the open frame or cage and when the motor is running in the other direction the carriage is caused to move downwardly in said frame or cage. Of course the motor may be stopped at any time and thus the desired position of the carriage with respect to the frame or cage may be attained. By reason of the screw threaded shafts it is apparent that when the motor is thus stopped the carriage is held against any movement under its own weight.

The means for driving or rotating the gear 30 is as follows :Adj acent and parallel with one of the screw threaded shafts is shaft 68 preferably of a rectangular cross section and the bottom end thereof is made cylindrical to be journalled in an antifraction bearing 69 in the bottom plate 16 while the top end of said shaft is also made cylindrical and is journalled in and extends above an antifraction bearing 70 in the top plate 19. Secured to said last mentioned end of the shaft is a beveled gear 71 with which meshes a pinion 7 2 fixed on one end of a transversely extending horizontal shaft 73 and said shaft is journalled in suitable bearings 74 on the channels 2222. The shaft is driven by sprockets and chains 7 5 from a motor 76 mounted on the plate 19. On the other end of the shaft 7 3 is a spur gear '77 and this gear meshes with a pinion 79 on the rotor shaft of a blower 80. The discharge side of this blower is connected by a flexible conduit 81 with the top end of a tube 82 carried by a spider on the plate 19 as best shown in Fig. 3 and the bottom end of which has a telescopic fit within the tube 54. Associated with the shaft 68 and positioned between the plates 26 and 27 of the carriage is a pinion 83 that meshes with the gear 30 and said pinion is journalled in top and bottom bushings 84 mounted in said plates. From the above description, it is apparent that the agitator may be driven irrespective of its position in the frame.

To more clearly illustrate the advantages and economy of our invention over the general practice of manufacturing manganese steel, the said present practice will be briefly described and then our improved method will be described whereby the comparison between the two will be more readily apparent.

In the'making of high carbon steel the general practice is to have the content of the steel bath or charge in the open hearth furnace down to .10 to .20 carbon, then to add sufficient molten pig iron to bring the carbon content up to the desired amount. Where a manganese steel is desired the general practice is to add manganese in the form of ferro-manganese containing about manganese, to the bath in the furnace before the recarburizer is added. This manganese added will vary from 400 to 2500 lbs., depending on the size of the charge and the manganese content desired in the finished product. The additional amount of manganese needed to bring the finished steel to the desired manganese content is usually added to the steel when it is poured into the ladle, with a limit of not more than 1% of the total steel charge of ferro-manganese to be added to the steel in the ladle.

The ferro-ma'nganese that is added to the bath or charge while it is in the furnace is usually in quite large lump form, some lumps weighing as much as 4.0 lbs. This lump form is used so as to cover a period of time while the recarburizer is being poured into the furnace and the furnace is being prepared for tapping. Quite a considerable amount of the ferro-manganese so added to the steel, while it is in the furnace is lost by oxidize.- tion. The usual recovery of manganese out of the 80% ferro-manganese so added is 48% of pure manganese in the steel.

The steel is then d awn out of the furnace through a hole in the bottom of the furnace, through a lined spout to the ladle. This spout is about 12 feet long. The steel drops from this spout to the bottom of the ladle, a distance of about 15 feet on a so-called ton ladle. This drop, of course, decreases as the ladle fills with molten steel.

The ferro-manganese, to be added to the steel, is usually in a chute, back of the furnace, with a spout so arranged that it can be swung to the center and somewhat above the ladle top. The spout is usually swung so that the alloys dropping into the ladle will strike the stream of molten steel coming from the furnace. The amount of alloy used will, of course, depend upon the desired results to be attained in the finished product, the idea bein to build up the manganese or other alloy to that which has already been added in the front of the furnace, so that the finished steel will be as close as possible to the specifications. The amount of ferro-manganese or ferro-silicon so added to the ladle will range from 600 to 2500 lbs., depending on the size of the charge of steel and the results desired.

The alloys added to the ladle are usually put in after about two feet of molten steel has been drawn from the furnace into the ladle and then at intervals as the ladle fills up. This addition of alloy is made slowly so as not to chill the molten steel in the ladle. The best practice is to so time the addition of alloy that the full amount will be added just before the slag starts to come from the furnace, which is the last material drawn from the furnace, due to the lighter weight of the slag causing it to float on top of the charge. The slag that comes from the furnace is allowed to drop into the ladle and from there it is drawn off through the slag spout on top of the ladle. A certain amount of slag is allowed to remain on top of the steel in the ladle, depending on how full the charge of molten steel drawn from the furnace fills the ladle. When the charge of steel in the furnace gets low, due to being drawn off into the ladle, a certain amount of slag mixes with this last steel to be drawn off and is carried into the ladle in this mixed form. This slag is a mixture of the lime, that has been added to the steel bath in the form of lime-stone, and the impurities of the original charge. It is very desirable that but a minimum amount of this slag get into the finished steel.

When alloys are added to the back of the furnace, which means to the molten steel in the ladle, they are usually in a cold state and as is apparent the molten steel in the ladle must supply the heat necessary to melt them. These alloys are usually in lump form and are of such a density that they are carried to the bottom of the molten steel in the ladle. Thus they chill the molten steel at the bottom of the ladle, which, by reason of being so chilled, stays at the bottom, with the lighter and hotter steel at the top of the ladle. This bottom steel is unable to melt but a limited amount of the alloys so added, especially when the alloys are added in quite a large lump form.

Present practice has shown that there is a much larger percentage of the manganese (contained in the ferro-manganese) recovered, by adding it to the ladle than where it is added to the front of the furnace. This recovery usually amounts to of the manganese contained in the ferro-manganese against an average of 48% where it is added to the charge while it is still in the furnace. In view of the scarcity and high cost of these alloys, the desirability of a saving thereof is indeed apparent and such a saving is attained in our improved method, because it is practical to add larger amounts of alloys to the steel while it is in the ladle.

It is evident that molten steel begins to drop in temperature as soon as it leaves the furnace and that a minimum temperature which will allow of good pouring into the last one of a battery of ingot moulds must be maintained because thereof, the time element existing between the tapping of the furnace and the pouring into the said last one of the ingot moulds is very important. The time necessary to tap an average charge of 100 to 125 tons of molten steel from an average open hearth furnace into a ladle is approximately 12 minutes. The time consumed in taking the ladle to the ingot pit and starting the first pour will approximate five minutes, figuring an average conditionand temperature of the steel. Somtimes it is necessary to hold the steel in the ladle before pouring so as to bring it down to a good pouring temperature. The time required to pour an average charge as above will be from 20 to 40 minutes, depending on the character of the steel and the size of nozzle used, different alloy steels pouring at different rates. It is thus evident that there will be a considerable difference or range in temperature between the steel poured into the first ingotmouldand the steel poured into the last one, and this range or difference in temperature of course causes a variance in the amount of alloy to be found in various ingots.

Due to the addition of ore to the steel, while it is still in the furnace, a large amount of gas is created in the molten steel. The usual practice is to wait two hours after such an addition of ore is made to the steel, before drawing it from the furnace, so as to allow time for these gases to pass off. Also in building the carbon content back to the desired amount, by the addition of molten pig iron, a certain amount of gas is created. This recarburizer also increases the temperature of the steel in the furnace. It will be readily seen that by all of these additions to the steel while it is still in the furnace there is bound to be certain amounts of gases, slag and other impurities in the steel after it is discharged into the ladle, which conditions are avoided in our improved method to a considerable extent.

Following are some figures relating to charges in an open hearth furnace:

Pounds Amount of scrap charged into furnace 150,000 Amount of pig iron charged into furnace 110,000

Total-c 260,000

If from the above figures, a steel with a manganese content of 1.45 is desired about 3,770 lbs. of manganese will be required. Of

this amount approximately 520 lbs. will be found to be in the original charge, and ap- .proximately 360 lbs. in the recarburizer that will be added. This recarburizer will amount to approximately 18,000 lbs. which will bring the total Weight of the charge to 278,000 lbs., which will be approximately the amount drawn from the furnace. This means that the total amount of manganese that must be added to the charge in order to bring the content up to 1.45 of the final amount, (namely 4031 lbs.) will be 3151 lbs. provided there was 100% recovery. As the present amount of ferro-manganese that can be added to the ladle is limited to 1% of the total charge, as before stated, it means that the total weight of ferro-manganese added to the ladle can only be 2780 lbs. The recovery of manganese from the ladle will be 68% of that amount in the ferro-manganese, which averages 80% manganese. Therefore 68% of 80% of 2780 lbs. or 1445 lbs. of manganese in the finishedsteel can be secured by adding to the ladle. The balance of the 3151 lbs. needed will have to be added in the furnace, which makes 17 06 lbs. to be secured through the furnace. Here the recovery is only 45% so that to secure an actual of 1706 lbs. there will be needed 4738 lbs. of ferromanganese of 80% manganese. This means that a total of 7518 lbs. of ferro-manganese must be added to the charge.

Taking up the same figures as above set forth in connection with an open hearth furnace charge we will now describe our improved method as may be most advantageously carried out by the structure described. Therefore assume with a blast furnace charge of approximately 278,000 lbs. the ladle is moved by the handling crane into position to receive a charge from the furnace, the agitator having been withdrawn from the ladle to that elevated position as will permit ready pouring into the ladle.

During the charging of the ladle a certain amount of ferro-manganese (of 80% manganese) is put into the ladle and settles to the bottom thereof and after the ladle has been charged the motor 64 is started to move the agitator into the ladle and when the proper level is reached the motor is stopped and the motor 76 is started to rotate the agitator. This agitator being fully protected by its refractory covering, in no way induces boiling of the charge and due to the inclination of the blades, the molten metal is not only agitated or stirred but an upward movement is also imparted thereto. This maintains an even temperature throughout the entire mass of metal and promotes a more ready melting of the alloy and a more thorough mixing of the same with the molten metal, at the same time releasing the confined gases and small particles of slag and other impurities.

By this system of agitation, the amount of ferro-manganese that can be added to the ladle can be increased. Taking the same example as above this would then mean that a total of 4170 lbs. of ferro-manganese could be added to the ladle. By this melting and mixing, a greater amount of the manganese in the ferro-manganese would also be recovered than is possible in the present practice. Figuring this recovery at 80% we would get a manganese recovery in the finished steel of 80% of 80% of 4170 or 2668 lbs. This would then require that the addition in the furnace supply a total of 483 lbs. in the finished product, which would mean an addition of 1341 lbs. of ferro-manganese in the furnace. Hence it is seen that by means of the improved process there will only be required a total of 5511 lbs. of ferro-manganese to get the same results or a savin of 2007 lbs. or a saving of 26%, which amounts to over $100.00 per heat, with 80% ferro-manganese at $100 per ton.

This system of agitation, mechanical in nature, will provide, in addition to the saving in alloys required, a steel that is more free from gases and impurities and one in which the alloys are more uniformly mixed. It will also tend to keep a more uniform temperature of the steel in the ladle during the time required for pouring it into ingots and thus make for more uniformity in the ingot. By releasing practically all of the gases in the steel and by keeping the temperature more uniform it will tend to decrease pipage in the ingot, which will eliminate a great amount of waste.

From the above mentioned description, it is apparent that the improved method, not only presents a great saving in material but also in time and produces a more uniform steel in the ingot. Furthermore the apparatus employed, in no manner renders the present apparatus obsolete but in fact is an addition thereto whereby such present apparatus may be readily changed over. The agitator mechanism may be readily raised or lowered to the desired lever and in no way interferes with charging the ladle or the pouring of the charge into the ingot molds.

lVhile in describing our invention, we have referred in detail to the form arrangement and construction of the parts thereof as well as to their manner of operation and to sequence of the steps of the method carried out thereby, the same is to be considered as illustrative only so that we do not wish to be limited thereto except as may appear in the more specific of the following claims.

lVe claim as our invention 1. The steps in the manufacture of an alloy steel, comprising drawing a heat of molten steel containing a certain percentage of alloy from a furnace into a ladle, adding a greater percentage of alloy to the molten metal in the ladle, and then mechanically agitating the metal and alloy while in the ladle and without the addition of extraneous heat, causing the central portion of the mixture to travel upwardly and the peripheral portion of the same to travel downwardly.

2. The method of producing a manganese steel comprising drawing a heat of molten steel containing a certain percentage of alloy from a furnace into a ladle, adding a greater percentage of alloy to the molten metal in the ladle, and then mechanically agitating the metal and alloy while in the ladle and without the addition of extraneous heat, causing the central portion of the mixture to travel upwardly andthe peripheral portion of the same to travel downwardly.

In testimony whereof, I have hereunto set my hand this 7th day of February, 1928.

HARRY WV. PROTZELLER.

In testimony whereof, I have hereunto set my hand this 7th day of February, 1928.

GEORGE WV. FINNEY. 

